/**
  *
  * @param  string  $folderId
  * @param  int     $filterType
  * @return Tinebase_Record_RecordSet
  */
 public function getServerEntries($folderId, $filterType)
 {
     $folderBackend = Syncroton_Registry::get(Syncroton_Registry::FOLDERBACKEND);
     $folder = $folderBackend->getFolder($this->_device, $folderId);
     $bigContentIds = parent::getServerEntries($folder->bigfolderid, $filterType);
     foreach ($bigContentIds as $bigContentId) {
         $contentId = md5($bigContentId);
         $contents[$bigContentId] = $contentId;
     }
     return $contents;
 }